修改配置文件：config_inc.php


$g_allow_file_upload    = ON;
$g_file_upload_method   = DISK;
$g_max_file_size                = 50000000;     # in bytes
$g_allowed_files        = 'txt,jpg,png,jepg,gif,bmp,zip,tar.gz,doc';
# $g_absolute_path_default_upload_folder = ''; # used with DISK, must contain trailing \ or /.
$g_absolute_path_default_upload_folder = '/data/upload'; # used with DISK, must contain trailing \ or /.
$g_preview_p_w_uploads_inline_max_size=99999999; 数值小的话会出现附件丢失的问题